Ergonomic input device

ABSTRACT

The device comfortably supports the hand of the user while the thumb and fingers are associated with keys, a trackball, and a scrolling wheel carried on the device. The overall configuration of the device and the arrangement of these actuators permits the user to operate all of the functions provided by the actuators while the forearm is in a neutral posture zone between pronation and supination of the forearm, and the wrist and fingers are minimally extended and comfortably flexed, respectively.

FIELD OF THE INVENTION

This invention relates to an ergonomically designed computer inputdevice.

BACKGROUND AND SUMMARY OF THE INVENTION

Computer input devices for entering commands into a computer are wellknown and currently available in a variety of configurations. Many suchinput devices include a rotatable ball mounted to the base of thedevice. As the ball is moved relative to the base, transducers sense themovement of the ball and generate signals indicative of the directionand amount of that movement. The signals are used, for example, tocontrol movement of a cursor on the screen of a computer.

A type of input device known as a "mouse," houses the rotatable ball sothat it extends from the underside to frictionally engage a worksurface, such as a desktop. The movement of the mouse along the worksurface causes rotation of the ball for generating the signals that areconverted to cursor movement on the computer screen. A trackball-typeinput device, on the other hand, has its rotatable ball exposed formanipulation by the user's finger(s) and/or thumb. Similar ball-positionsignals are generated.

Computer input devices also include keys. Depressing one of the keyschanges the state of an associated switch, which permits a user to entervarious commands into the computer. The nature of the command usuallydepends upon the position of the cursor on the screen.

One mouse-type pointing device, available from Microsoft Corporationunder the trademark IntelliMouse, includes a roller or wheel thatprotrudes from the top of the device and is coupled to a transducer forproducing a signal indicating the rotation of the wheel. That signal maybe used, for example, for scrolling through a window displayed on acomputer, which function was heretofore performed by moving the cursorto the window "scroll bar" and depressing a key as needed to scrollthrough whatever is displayed in the window. For convenience, the wheelwill be hereafter referred to as a "scrolling wheel." The keys,trackball, and scrolling wheel may be collectively referred to as theactuators carried on the input device.

Irrespective of the type of input device employed, mouse or trackball,it is important that the device be comfortable for the user to operate,especially over long periods of time. Such comfort is obtained bycareful attention to ergonomic factors, particularly toward minimizingstress in the user's fingers, wrist, and forearm. Providing acomfortable computer input device can be especially challenging whenone's design goal includes enhancing the function of the device overwhat went before, such as by combining, along with keys and a trackball,an actuator like the aforementioned scrolling wheel.

The present invention is directed to an ergonomic input device thatcomfortably supports the hand of the user while the wrist is minimallyextended and the thumb and fingers are oriented in neutral postures foroperation of the actuators carried on the device. The overallconfiguration of the device and the arrangement of these actuatorspermits the user to carry out all of the functions provided by theactuators while the forearm is in a neutral posture zone, betweenpronation and supination of the forearm.

More particulary, the base of the device is shaped so that themetacarpal-phalangeal joint ridge is supported, as is the remainder ofthe user's palm. In this regard, the palm is considered here to comprisethe metacarpal-phalangeal joint ridge (which, for the present, can bethought of as the area where the fingers are jointed to the end of thepalm), the thenar eminence (the mound of the palm at the base of thethumb), and the central region of the palm that defines what is known asthe palm gutter.

The size and shape of the device is such that a wide range of hand sizeswill be comfortably supported in using the device, including those handsizes falling within a range defined by the fifth percentile female(small hand) to the ninety-fifth percentile male (large hand) of NorthAmerican adults.

The actuator arrangements and shape of the device also minimizesextension of the wrist and fingers. Abduction and adduction of thefingers is also minimized.

Moreover, the actuators are located such that the primary actuator(trackball) is oriented for manipulation by the finger with the greatestdexterity; namely, the index finger. Secondary functions, such asdepressing the keys "clicking") and operating the scrolling wheel areassigned to the slightly less dextrous digits, the thumb and middlefinger, respectively. The even less-dextrous ring finger and littlefinger are not associated with any actuators but are instead comfortablysupported by the base of the device, in a manner that facilitates acomfortable overall grip or feel of the device and act as resistance tobutton activation force vectors by the thumb.

The foregoing and other features and advantages of the preferredembodiments of the present invention will be more readily apparent fromthe following detailed description, which proceeds with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a right-handed version of an ergonomicinput device in accordance with the present invention, also depicting adiagram of a computing system with which the device may be employed.

FIG. 2 is a diagram of a right-hand skeleton from a top plan view.

FIG. 3 is a side elevation view showing one, "inner," side of thedevice, including a user's hand positioned for operating the device.

FIG. 4 is a top plan view of the device.

FIG. 5 is a side elevation view, like FIG. 3, but without user's hand.

FIG. 6 is a perspective view of the device showing a user's hand withfingers associated with the respective actuators.

FIG. 7 is another perspective view of the device, which view bestillustrates the preferred positional assignments of the user's ring andlittle finger.

FIG. 8 is a side elevation view of the outer side of the device, whichis opposite the inner side.

FIG. 9 is a back elevation view of the device.

FIG. 10 is a front elevation view of the device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 3 depict an ergonomic input device 20 configured inaccordance with the present invention. The device includes a base 22having a flattened bottom 23 (FIG. 3) for resting on a planar worksurface, such as a desktop 25. In a preferred embodiment, the body 22includes an upper housing 24 that is joined to a lower housing 26. Fourindependently-operated actuators are carried by the body, including aprimary key 28, a secondary key 30, a trackball 32, and a scrollingwheel 34.

The primary key 28 and secondary key 30 may be depressed. A switchingfunction is carried out by depressing each key, like that functionperformed by a conventional mouse when one depresses or "clicks" a key.Specifically, depressing either of the keys 28, 30 changes theassociated switch state and generates a signal that is conveyed viaconductors in a cord 36 to a computer 40. One end of the cord 36 isanchored inside of the device body 22. The cord emanates from the frontor distal end 38 of the device, and the other end of the cord is coupledwith the computer 40.

The computer 40 may be any of a multitude of designs and includes avisual display device 42. The device 42, which may be a cathode raytube-type, active matrix display, or other suitable device, can displaya cursor or pointer 44, along with text and other graphic information.The computer also includes storage or memory 46, a processor 48, and akeyboard 50.

The trackball 32 is mounted for rotation about any axis. Encoders housedwithin the base 22 detect the motion of the trackball and convey signalsvia cable 36 to the computer in a conventional manner. Those signals maybe employed, for example, for moving the pointer 44 across the display42.

The scrolling wheel 34 may be of the type embodied in the previouslymentioned product produced by Microsoft Corporation under the trademarkIntelliMouse. More particularly, the wheel 34 is supported on an axlethat resides within the body 22 of the input device. That axle iscarried by spaced-apart axle supports. The axle supports are configuredto allow one end of the axle to move in a direction that is generallyperpendicular to the axis of rotation of the wheel, so that the wheelmay be depressed, slightly tilting its axle to activate a switch. Aspring is contained within the housing and arranged to resist depressionof the wheel.

An optical encoder may be positioned on the axle for rotation with thewheel. A light source and a light sensor may be mounted within thedevice so as to sense the motion of the optical encoder to provide apositioning signal. The switch that is engaged as a result of depressionof the wheel, provides a switching signal. A detent mechanism may alsobe provided on the axle to provide a segmented feel to the rotation ofthe wheel. The wheel position and switch signals are conveyed via thecable 36 to the computer for effecting changes on the visual display,such as scrolling, etc.

Before proceeding with the ergonomic and associated characteristics ofthe input device of the present invention, it will be worthwhile tooverview concepts and terminology of interest. This is accomplished inpart by reference to FIGS. 2 and 3. Shown in FIG. 2 are the five majorhand bones radiating from the wrist area, which are known as themetacarpals 60. The finger bones number fourteen in each hand and aredesignated phalanges 62. It is noteworthy here that although theembodiment under consideration represents a right-hand input device, amirror image, left-hand version of the device may be readily provided byreference to the following description. Accordingly, a right hand isdepicted in FIGS. 2 and 3. In this description, the particular fingerswill carry conventional designations; namely, from right to left in FIG.2, the thumb, and the index, middle, ring, and little fingers.

Where each finger meets the palm or, more precisely, where themetacarpal bones 60 and phalangeal bones 62 of the fingers join, thereare defined metacarpal-phalangeal joints 66, 68, 70, 72. Ametacarpal-phalangeal ridge 64 is defined by the portion of the hand inthe vicinity of these four joints. Thus, the ridge 64 includes thesecond (finger) metacarpal-phalangeal joint 66, the third 68, fourth 70,and fifth 72, as depicted in FIG. 2. As will become clear upon readingthis description, the input device of the present invention isconfigured to support he metacarpal-phalangeal joint ridge 64 so thatthe user's hand and arm remain comfortable, and the thumb, index andmiddle fingers may comfortably manipulate associate actuators.

The ranges and specific dimensions for the embodiment described hereinwere arrived at through the use of anthropometric data, biomechanics andobservation-based methodology. Given, however, that most of the edgesand surfaces of the preferred embodiment are curved, it will beappreciated by one of ordinary skill in the art that ordinarymeasurements taken from or to a curved edge are accurate within a rangeof about 1 millimeter, and minor deviations from the stated ranges ordimensions will not adversely affect the ergonomic advantages provided.

Ergonomic criteria for each point of contact between the user and theinput device is quantified and incorporated such that the user may graspand use the device in a biomechanically neutral position. Such a neutralposition is achieved when the flexors and extensors of the user's handand wrist are in equilibrium, where intracarpal pressure is minimizedand flexors and extensor muscles are positioned for optimal applicationof strength. A biomechanically neutral zone is achieved when the user'sforearm is between pronation and supination and, as respects the wrist,when the user can control the device with the wrist not exceeding amaximum extension of about 10 degrees, a maximum radial deviation ofabout 26 degrees, and a maximum ulnar deviation of about 45 degrees. Asillustrated in FIG. 2, with a hand on a flat surface, radial deviationis rotation of the wrist toward the thumb and ulnar deviation isrotation of the wrist toward the little finger. Both deviations aremeasured relative to the axis 74 passing through the center of the wristjoint 76.

As illustrated in FIG. 3, wrist extension is measured as an acute anglecreated by an inclination of the hand plane 78 relative to a horizontalaxis 80 passing through the center of the wrist joint 76. The hand plane78 is defined as that plane within which reside the second through fifthmetacarpal bones.

The present invention provides an ergonomic input device that willaccommodate hands sized within a range of a fifth percentile female to aninety-fifth percentile male, considering North American adults.Alternatively, users having hands falling outside of this design rangemay still enjoy the advantages of the invention, by appropriatelyscaling up or down the configuration of the present embodiment.

With particular reference to FIGS. 1, 3, and 5, the base 22 of thedevice 20, which may be formed of rigid plastic, has a flattened bottom23 that rests on a surface 25 while being operated. That is to say, thedevice is intended to be stationary during use, no positional signalsare generated as a result of moving the body of the device relative tothe surface 25. Nevertheless, the device is shaped to be comfortablygripped by the user while changing its position on the desktop to suitthe user. During use, the overall device is comfortably felt between thethumb and little finger, as will be explained.

With particular reference to FIG. 5, the base 22 includes a proximal end82 and a distal end 38. In a preferred embodiment, the overall length ofthis device is about 150 millimeters. The side of the device appearingin FIG. 5 is hereafter designated the inner side 84, and is the sidethat carries the thumb-contacted keys 28, 30 as discussed more fullybelow.

Along the top of the device, the inner surface 84 joins an upper surface86. The device is configured so that between the proximal end 82 and thedistal end 38 the device is thickest in the region just slightly distalfrom (that is, to the left in FIG. 5) the mid-point between the proximalend 82 and distal end 38. This thickness is preferably about 48millimeters and is represented by dimension line 90, measured in adirection perpendicular to the flattened bottom 23 of the device.

As respects a front elevation view and back elevation view (see FIGS. 9and 10) this thickest part of the device 20 is adjacent to the innerside 84 of the device. The portion of upper surface 86 associated withthis thickest part is designated as a crest 88 from which the thicknessof the device gradually diminishes in a direction away from the crest88.

Considering the profile provided by the back elevation view (FIG. 9),the thickness diminishes gradually along a negative-sloped upper surfacecurve so that the thickness of the device at the midpoint, appearing asdimension 92, is about 43 millimeters. From that location, in thedirection away from the crest 88, the profile slope diminishes somewhatmore rapidly such that, at a location shown as dimension 94, which isvery near the junction of the upper surface 86 and the outer surface 96,the thickness of the device is about 23 millimeters.

The junction of the upper surface 86 with the inner surface 84 and thejunction of the upper surface with the outer surface 96 (for thatmatter, the entire periphery of the upper surface 86) is gently roundedso that no sharp edges are presented to the user, which edges wouldintroduce uncomfortable pressure ridges when the device is operated asexplained below. In this regard, the peripheral edge of the uppersurface, which is depicted as immediately adjacent the perimeter lineappearing in FIG. 4, is shaped to have a radius of no less than about 3millimeters along the junction of the top surface 86 with an associatedside. Such a radius is shown at 98 in FIG. 9.

With reference to FIG. 5, the thickness of the device is such that thereis defined in the profile of the device (FIG. 5) a negative-slope curvehaving a high point at the crest 88 and diminishing gradually to aheight, shown as dimension 100, of about 18 millimeters adjacent towhere the upper surface 86 of the device joins the distal end 38 of thebody 22. Similarly, the profile of the device from the crest 88 in thedirection toward the proximal end 82 diminishes in a negative-slopecurve to a dimension 102 adjacent to where the upper surface 86 joinsthe proximal end 82 of the device. The thickness 102 is about 18millimeters.

The trackball 32 is a sphere, preferably having a diameter of 38millimeters, and is mounted to the body so that its center 33, as viewedin plan (FIG. 4) is located midway between the crest 88 and the distalend 38 of the device. This optimal placement corresponds to the distancefrom the crest 88, where support is provided to themetacarpal-phalangeal ridge 64, to the center 33 of the trackball inorder to be actuated by the tip of the index finger 106 (See FIG. 3) ofany hand falling within the range of sizes from a small, fifthpercentile female hand to a large, ninety-fifth percentile male, amongNorth American adults.

As shown best in FIGS. 1 and 10, the portion of the upper surface 86 ofthe device 20 surrounding the trackball 32 is recessed. The depth ofthis recess 101 from the surface, as measured from the junction of therecess and the ball (along a tangent to the ball) is about 5-7millimeters, as shown as dimension 102 in FIG. 10. Substantially anentire hemisphere of the trackball 32 is exposed for manipulation by theindex finger 106 of the user, as will be explained.

With reference to FIGS. 3 and 6, the device 20 is shown with the user'shand placed in a position for operating the device. In such a position,the region of the user's hand underlying the secondmetacarpal-phalangeal joint rests upon or is supported immediatelyadjacent the crest 88 of the upper surface 86. The index finger 106 iscomfortably flexed so that its tip contacts and is able to manipulatethe trackball 32. In this regard, the trackball is spaced a minimumdistance from the crest 88 of the upper surface 86 to facilitateoperation of the trackball by moving the index finger through acomfortable range of flexion and extension from a neutral, slightlycurled position. In a preferred embodiment, this distance, as measuredfrom the crest 88 to the nearest point on the trackball 32, is about thedistance corresponding to the radius of the trackball. Alternatively,the trackball could be comfortably located at a distance of about oneand one-half radii, although the one-radius distance is preferred.

As noted above, the preferred size of the trackball is about 38millimeters in diameter. The just described crest-to-distance spacing(that is, as related to trackball radius) would vary accordingly were alarger or smaller trackball employed.

The elevation of the top 35 of the trackball 32 (FIG. 5) is such that itis about the same as or slightly lower than the thickness of the deviceat the crest 88. This relationship between the height of the trackballand the crest 88 provides the advantage of reducing the extension of thewrist and index finger that would otherwise be required if the top ofthe trackball were above the crest of the device. In a preferredembodiment, the top 35 of the trackball is 46 millimeters above the flatbottom 23 of the base 22, 2 millimeters below the crest 88.

The above-mentioned recess 101 that surrounds the trackball 32 (FIG. 10)permits exposure of the entire hemisphere of the trackball 32 at aheight, as measured perpendicularly from the flattened part of the base,that is relatively lower than would be the case if the hemisphere of thetrackball were exposed without a surrounding recess. Put another way,the recess plays a role in the ergonomic advantages of reducing theextension of the user's index finger.

Turning now to consideration of the keys 28, 30 mounted on the innersurface 84 of the device, and with particular reference to FIGS. 3, 4and 5, it is noteworthy that each key is defined in part by a contactsurface 29, 31 against which is pressed the thumb 108 of the user toactuate the underlying switch. The contact surface 29 of the first orprimary key 28 is shaped so that the surface normally (that is, when thekey is not depressed) is flush with the slightly concave portion of theinner surface 84 that surrounds it. The surface 29 is concave.

A thin, slightly protruding ridge 110 provides a distinctive tactilefeel, thereby allowing a user to distinguish between the primary key 28and the secondary key 30 without viewing those keys. In the preferredembodiment, the primary key and the switching associated with it may beassigned functions that are normally assigned to the left key of aright-handed mouse, which means that under normal circumstances, theprimary key 28 would be actuated more often than the other, secondarykey 30. Thus, the area assigned to the primary key 28 is preferablyrelatively larger than the area assigned to the secondary key 30. Thecontact surface 29 of the key 28 is shown between the intersecting arcsthat surround the key.

Inasmuch as the contact surface 29 of the key 28 is flush with the innersurface 84 of the device, one will appreciate that the user's thumb 108will be readily moved between the primary key 28 and the secondary key30 (compare FIGS. 3 and 6) with practically no extension of the thumb.That is, the thumb need not be moved away from the side surface of thedevice in order to move into contact with a key, which movement would benecessary if the key, for example, were protruding from the innersurface. As a result, access to either key occurs with comfortable sideto side (lateroflexion) motion of the thumb 108. Depression of the keysoccurs with slight flexion of the thumb. Thus, the access and actuationof the keys by the user's thumb are within the expected range of thumbmotion for a wide range of hand sizes. Moreover, the slight concaveshape of the contact surfaces 29, 31 conforms to the convex shape of theuser's thumb, thereby ensuring that practically no extension of thethumb is required in moving from key to key.

Yet another advantage of the ergonomic configuration of the device canbe best appreciated while considering the view of FIG. 4, the top planview. In this regard, the trackball 32 is mounted to be near the innerside 84 of the device body 22. The closeness of the side surface (hence,the keys 28, 30 contacted by the thumb) and the trackball 32 minimizesthe abduction of the thumb and index finger required to respectivelyoperate the keys and trackball. Put another way, the angle between thethumb and index finger is minimized with this configuration. In apreferred embodiment, the nearest point of the trackball 32 to theextension of the surface (the dimension 112 shown in FIG. 4) is no morethan the distance corresponding to one and one-half radii of thetrackball 32. Preferably, this distance measures about one such radius.

The scrolling wheel 34 is mounted next to the trackball 32 away from theinner side 84 of the device. In plan view (FIG. 4) the wheel 34 presentsa regular ellipse shape. The wheel is mounted in the downwardly slopingdistal part of the upper surface 86 of the device, and is surroundedwith a recess 103 having a maximum depth, where the surface is adjacentto the wheel, matching that of the recess surrounding the trackball. Therecess 103 surrounding the wheel 34 enables a given portion of the wheelto be exposed for contact (in a preferred embodiment, about the topone-third height of the wheel) at an elevation lower than would be thecase if the wheel were mounted without a surrounding recess. In apreferred embodiment, the top of the wheel is about 30 millimeters abovethe flattened surface of the device, as measured along a lineperpendicular to that surface.

The recess 103 surrounding the wheel 34 is contiguous with the recess101 surrounding the track ball 32. As a result, the user's index finger106, which is comfortably assigned to rotating the trackball 32, ormiddle finger 111, which is comfortably assigned to rotating the wheel34, can be moved back and forth between the wheel and the trackballwithout contacting the upper surface as might be the case if there werea bridging, non-recessed portion of the upper surface between the wheeland the trackball. The contiguous recesses, therefore, facilitate theabduction and adduction of the index finger as it moves between thetrackball and the wheel or the middle finger as it moves between thetrackball and the wheel, as the user prefers.

As noted, the finger with the greatest fine motor control and speed, theindex finger 106, will rest with its tip comfortably contacting thetrackball 32 while the tip of the middle finger engages the wheel 34.The ring finger 120 is not intended to be employed for moving any of theactuators carried by the device. In this regard, as shown in FIGS. 4 and7, the device is shaped so the upper surface 86 includes a smooth,generally upward facing portion between the wheel 34 and the outersurface 96 that is of sufficient width to support the ring finger 120while the device is being operated (that is, while the thumb, index, andmiddle fingers attend to the actuators).

The user's little finger 124 drapes comfortably along the outer side 96of the device (FIG. 5). The user's ring finger 120 sits comfortablyalong the curved or "radiused" edge of the outer side of the device andthus may be moved along the outer side 96 of the device as desired orneeded by the user. Thus, the little and ring fingers fit over a portionof the outer surface that is roughly parallel to the opposing innersurface portion of the device. As a result, the device 20 residesbetween the thumb and the little and ring fingers during use, or whenbeing repositioned on the desktop, and provides a very comfortable gripor "feel" for the user.

The height of the outer surface 96 is such that the tip of the littlefinger 124 may contact both the outer surface 96 and the desktop surface25 with the finger slightly curled and with very little abduction ofthat finger. The contact of the little finger tip and the desk providesthe user with a tactile "anchor" of the device on the desktop.

The foregoing finger/actuator assignments provide easy finger motion formoving those particular actuators. This ease and comfort is attributablein no small part to the nature in which the user's palm is supported bythe proximal part of the upper surface of the device (that is, the areabetween the crest 88 and the proximal end 82 between the inner side 84and outer side 96).

As pointed out earlier, one can consider the crest 88 as the area datumon or near which the region underlying the user's secondmetacarpal-phalangeal joint is supported by the surface 86. Put anotherway, the crest 88 can be considered an ergonomic datum point or areaproviding a strong visual cue (in combination with the arrangements ofthe keys, trackball, and wheel) for where the user is to place the palmfor most comfortable and efficient use of the device.

For smaller hands, such as a fifth percentile, North-American femalehand, the operating position of the palm will be such that the regionunderlying the second metacarpal-phalangeal joint will rest nearlydirectly over the crest. Larger hands, such as a ninety-fifthpercentile, North-American male, will engage the device so that theregion underlying the second metacarpal-phalangeal joint rests slightlyaway from the crest 88 in a direction toward the proximal end 82 of thedevice. It will be appreciated that in the drawings accompanying thepresent description a relatively large hand is depicted.

Irrespective of the size of the hand operating the device 20, exposedupper surface 86 between the proximal end 82 and the trackball 32 isconfigured to support the metacarpal-phalangeal ridge 64, as mentionedabove, so that the user's forearm is in the neutral zone betweenpronation and supination. In this regard, a dashed line 130 is depictedin FIG. 4 to illustrate the location on the surface 86 where thecenterline of the metacarpal-phalangeal ridge 64 will rest as the useroperates the device. The remaining portion of the palm, including thethenar eminence and palm gutter, are filled with the continuous convexcurve of the upper surface 86 in this region. That is, there are novoids or sudden changes in the curvature in this region, which mightleave a gap or indentation beneath the user's palm thereby removing acorresponding amount of palm support that would have to be taken up withan increased static load on the users hand and arm muscles.

Small hands may engage the device 20 in a way so that the entire palmabove the wrist is supported by the surface 86. Relatively larger handswill have substantially all of the palm so supported, except for thevery base of the palm where the palm gutter joints the wrist. The baseof the large palm fits comfortably over the rounded proximal end, andmay rest on the desktop 25.

Having illustrated and described the principles of the present inventionin a preferred embodiment, it should be apparent to those skilled in theart that the embodiment can be modified in arrangement and detailwithout departing from such principles. Accordingly, we claim as ourinvention all such embodiments as come within the scope and spirit ofthe following claims and equivalents thereto.

We claim:
 1. An input device, comprising:a body having an upper surface,an inner surface and an outer surface, a portion of the upper surfacebeing exposed for supporting the palm of a user's hand with the user'shand in an operating position. first and second rotatable membersrotatably mounted to the upper surface, the first and second rotatablemembers being arranged to be operable by the user's index and middlefingers, respectively; and first and second keys mounted to the innersurface, the first and second keys being individually depressible by theuser's thumb while the user's palm is in the operating position.
 2. Thedevice of claim 1 wherein, apart from the first and second keys and thefirst and second rotatable members, no other components are provided onthe body for actuation by a finger of the user while the user's hand isin the operating position.
 3. The device of claim 1 wherein the firstrotatable member is a trackball that is rotatable about more than oneaxis.
 4. The device of claim 3 wherein the second rotatable member is awheel.
 5. The device of claim 1 wherein the outer surface issubstatially opposite the inner surface and wherein the second rotatablemember is spaced from the outer surface by an amount sufficient topermit the user's ring finger to rest on the upper surface between thesecond rotatable member and the outer surface.
 6. The device of claim 5wherein the second rotatable member is located on the upper surface tobe aligned with the user's middle finger and is between the trackballand the outer surface.
 7. The device of claim 6 wherein the center ofthe trackball and the center of the wheel are spaced apart by an amountless than amount 30 millimeters, thereby to minimize the amount ofabduction required of the index and middle fingers as the index fingertouches trackball and as the middle finger touches the wheel while theuser's hand is supported in the operating position.
 8. The device ofclaim 1 wherein the center of the first rotatable member and the centerof the second rotatable member are spaced apart by an amount less thanabout 30 millimeters, thereby to minimize the amount of abductionrequired of the index and middle fingers as the index finger touches thefirst rotatable member while the user's hand is supported in theoperating position.
 9. An input device, comprising:a body having a flatbottom portion for resting on a support surface, a curved upper surface,an inner surface and an outer surface, the curved upper surface having acrest defining the thickest part of the device as measuredperpendicularly to the curved upper surface exposed for supporting atleast part of the palm of a user's hand; a spherical member having acenterpoint and a radius and being rotatable mounted to the body toprotrude from the upper surface and arranged for manipulation by theindex finger of the user while the user's palm is supported on the uppersurface, the spherical member being spaced about a one-radius distancefrom the crest, thereby to facilitate support of the user's hand withthe region underlying the second metacarpal-phalangeal joint upon thecrest while the tip of the user's index finger rests on the sphericalmember, wherein the portion of the upper surface surrounding thespherical member is recessed, thereby to expose a hemisphere of thespherical member at a height, as measured perpendicularly from the flatbottom portion, relatively lower than would occur if the hemisphere wereexposed without a recess in the surrounding upper surface portion; adepressible key mounted to the inner surface and exposed for contact bya user's palm is supported on the upper surface; and the device beingconfigured and arranged so that the centerpoint of the spherical memberis closer to the inner surface than to the outer surface and so that theinner surface is spaced no more than about a one and one-half radiidistance from the spherical member, thereby to minimize the distancebetween the user's thumb and index finger as the spherical member ismanipulated by the index finger and the key is contacted by the thumb.10. The device of claim 9 wherein the inner surface is spaced about oneradius from the spherical member.
 11. The device of claim 9, furthercomprising:a wheel rotatably mounted to the body to protrude from theupper surface of the body and arranged for manipulation by the middlefinger of the user while the user's palm is supported on the uppersurface; and wherein the device is configured and arranged so that thedistance from the wheel to the spherical member is no more than aboutone and one-half radii of the spherical member, thereby to minimizeabduction required of the user's index and middle fingers as thespherical member is manipulated by the index finger and the wheel ismanipulated by the middle finger.
 12. The device of claim 11 wherein thedistance from the wheel to the spherical member is no more than aboutone radius of the spherical member.
 13. The device of claim 9 whereinthe crest is adjacent to the side surface and the thickness of thedevice gradually diminishes in a direction away from the crest andtoward the outer surface, so that the user's metacarpal-phalangeal jointridge is supported such that the user's forearm is in a neutral zonebetween pronation and supination.
 14. The device of claim 13 wherein theupper surface from a location continuous with the crest is disposed in acontinuous slope in the direction away from the crest beneath the user'spalm thereby to support the user's palm, including the thenar eminenceand the palm gutter.
 15. The device of claim 9 wherein the user may havea hand sized within a range of a 5^(th) percentile female to a 95^(th)percentile male of North American adults and wherein a hand sized withinthe range will be supported on the device with the crest substantiallyadjacent to and supporting the region underlying the secondmetacarpal-phalangeal joint of the hand while the tip of the user'sindex finger rests on the spherical member and while the thumb of thehand contacts the key.
 16. The device of claim 15 further comprising:awheel rotatable mounted to the body to protrude from the upper surfaceand arranged for manipulation by the middle finger of the user while theuser's palm is supported on the upper surface; and wherein a hand sizedwithin the range will be supported on the device with the middle fingertouching the wheel.
 17. The device of claim 9 wherein the uppermost partof the spherical member, as measured perpendicularly from the flatbottom portion, is substantially the same or lower than the crest. 18.The device of claim 9 wherein the uppermost part of the sphericalmember, as measured perpendicularly from the flat bottom portion, issubstantially the same or lower than the crest.
 19. A computer inputdevice carrying at least one actuator that is operable for providinginformation to a connected computer, the device comprising: a bodyincluding:an inner surface;an outer surface substantially opposite theinner surface; a proximal portion adapted to support at least part ofthe palm of a user's hand while the user's hand is in an operatingposition; a distal portion adapted to carry at least one actuator formanipulation by a finger of the user while the user's palm is in theoperating position; a flat bottom portion adapted for resting on asupport surface; and a curved upper surface having a crest defining thethickest part of the device as measured perpendicularly to the bottomportion, wherein the crest is adjacent to the inner surface and thethickness of the device gradually diminishes in a direction away fromthe crest and toward the outer surface, so that the user'smetacarpal-phalangeal joint is supported with the palm in the operatingposition such that the user's forearm is in a neutral zone betweenpronation and supination; and a depressible key mounted on the innersurface and having a slightly concave contact surface adapted forcontact with the thumb of the user while the user's palm is in theoperating position.
 20. The device of claim 19 wherein the key isdepressible but normally disposed such that the contact surface issubstantially flush with the inner surface.
 21. The device of claim 20wherein the key contact surface is slightly concave shaped.
 22. Thedevice of claim 19 further comprising a second key mounted on the innersurface adjacent to the other key and having a contact surface forcontact with the thumb of the user while the user's palm is in theoperating position.
 23. The device of claim 22 wherein the second key isdepressible but normally disposed such that the contact surface issubstantially flush with the inner surface.
 24. The device of claim 23wherein the second key is depressible and the contact surface thereof isslightly concave shaped.
 25. The device of claim 19 further comprisingan actuator including a rotatable member carried by the distal portionand mounted to protrude from the upper surface and arranged formanipulation by the index or middle finger of the user while the user'spalm is in the operating position.
 26. The device of claim 25 whereinthe rotatable member is spaced distally from the crest in the directionthat the user's fingers extend while the user's palm is in the operatingposition, thereby to facilitate support of the user's hand with thecrest adjacent to the region of the hand underlying the secondmetacarpal-phalangeal joint, while the tip of the user's index or middlefinger rests on the rotatable member.
 27. The device of claim 25 whereinthe uppermost part of the rotatable member, as measured perpendicularlyfrom the flat bottom portion, is at an elevation substantially the sameas or lower than the crest.
 28. The device of claim 25 wherein therotatable member is a spherical member having a radius and beingrotatably mounted to the body to protrude from the upper surface; andwhereinthe device is configured and arranged so that the inner surfaceis spaced no more than about a one and one-half radii from the sphericalmember, thereby to minimize the distance between the user's thumb andindex finger as the spherical member is manipulated by the index fingerand the key is contacted by the thumb.
 29. The device of claim 28wherein the inner surface is spaced no more than about one radius fromthe spherical member.
 30. The device of claim 28, further comprising:awheel rotatably carried by the distal portion and mounted to protrudefrom the upper surface, and arranged for manipulation by the middlefinger of the user while the user's palm is in the operating position;and wherein the device is configured and arranged so that the distancefrom the wheel to the spherical member is no more than about one andone-half radii of the spherical member, thereby to minimize abductionrequired of the user's index and middle fingers as the spherical memberis manipulated by the index finger and the wheel is manipulated by themiddle finger.
 31. The device of claim 30 wherein the distance from thewheel to the spherical member is no more than about one radius of thespherical member.
 32. The device of claim 30 wherein the distance fromthe wheel is spaced from the outer surface by an amount sufficient topermit the user's ring finger to rest on the upper surface between thewheel and the outer surface.
 33. The device of claim 28 wherein the usermay have a hand sized within a range of a 5^(th) percentile female to a95^(th) percentile male of North American adults and wherein a handsized within the range will be supported on the device with the crestlocated for supporting the second metacarpal-phalangeal joint of thehand while the tip of the user's index finger rests on the sphericalmember and while the thumb of the hand contacts the key.
 34. The deviceof claim 19 wherein the upper surface contiguous with the crest isdisposed in a continuous slope in the direction away from the crestbeneath the user's palm thereby to support the user's palm, includingthe thenar eminence and palm gutter.
 35. In a manually operated inputdevice connected to a computer for providing cursor movement andswitching information to the computer to which the input device isconnected, an improvement comprising:a body having a flat bottom portionfor resting on a flat surface and an upper surface for supporting atleast a portion of a user's hand in a position for manually operatingthe input device; and first and second rotatable members adapted toprovide input to the computer as a function of their rotation, the firstand second rotatable members mounted to the body and exposed formovement by the fingers of a user, thereby to operate the input device.36. The device of claim 35 wherein one of the rotatable members ismounted for rotation and depression by a finger.
 37. The device of claim35 wherein only one rotatable member is mounted for rotation about morethan two axes.
 38. The device of claim 35 wherein the uppermost part ofboth rotatable members is substantially the same or lower than thethickest part of the device, as measured perpendicularly from the flatbottom portion.
 39. The device of claim 35 wherein the portion of theupper surface surrounding at least one of the rotatable members isrecessed.
 40. The device of claim 39 wherein the portion of the uppersurface surrounding both of the rotatable members is recessed.
 41. Thedevice of claim 40 wherein the recess surrounding the first rotatablemember is contiguous with the recess surrounding the second rotatablemember.